Glossary of Terms : K - O


The floor area in front of the lift entrance.

Landing door

A door in the opening of a lift shaft. Provides safe access to the lift car.

Landing entrance

An assembly that includes the landing doors and any architectural finishes associated with the entrance to the lift shaft.

Landing Zone

A zone extending from a point 300mm below a lift landing, to a point 300mm above the lift landing.


A scaled mechanical drawing showing dimensioned plan views and elevations of a lift hoistway and machine room to indicate space conditions, pertinent dimensions, sizes and location of components of the installation.


The movement of a lift toward the landing sill when it is within the levelling zone. When the word levelling is used, the inference is that the process of attaining a level stop or position (the platform level with the landing sill) is performed completely automatically.

Levelling Zone

The limited distance above or below a lift landing within which the levelling device is permitted to cause movement of the lift car toward the landing.


A device, which feeds oil to the guide rail and provides lubrication for sliding shoes.

Machine room

A room where the lift machine and some electrification and control system components are located. Usually located above the lift shaft.

Main contactor

A contactor which switches the power to the hoisting motor if 1) there is a need to run the lift car and 2) the electric safety chain is complete (closed).

Main entrance floor

The floor providing the main access to a building.

Main power supply

The devices that provide power to the lift. Also known as mains.

Motor Control

That portion of a control system that governs the acceleration, speed, retardation, and stopping of the moving lift.


A system used with automatic door operation which will give a warning signal and close the doors at a reduced speed and torque. Nudging is activated if the door remains open longer than a predetermined time.

Oil Buffer

One type of buffer which uses a combination of oil and spring to cushion the lift. It is located in the lift pit.

Oil Line

The pipe that channels the oil from the power unit to the jack.

Out of service switch

A key operated switch which is used to take the lift out of normal use.

Over Travel

A short distance beyond the terminal floor as allowance for building inaccuracies, manufacturing or installation inaccuracies.

Overspeed governor

A device which, when the lift attains a predeterminated speed, causes the lift to stop, and if necessary causes the safety gear to be applied.

Overspeed Governor Switch

It is actuated by centrifugal force and trips a switch when the lift speed has increased 15 per cent over its rated nameplate speed.